initial parser

diff --git a/calc.c b/calc.c
index 6414c2df28f98b7b5b8ffdf1574a6abbda7d3960..5c57927af9348aa09084704c4bc783147b014c4f 100644 (file)
--- a/calc.c
+++ b/calc.c
@@ -1,6 +1,6 @@
 /* depend: */
 /* cflags: */
-/* linker: atoi.o fdprintf.o */
+/* linker: atoi.o fdprintf.o parser.o */
 
 //#include <malloc.h>
 #include <stddef.h>
@@ -8,7 +8,9 @@
 #include <unistd.h>
 
 #include "atoi.h"
+#include "debug.h"
 #include "fdprintf.h"
+#include "parser.h"
 
 /* constants */
 
@@ -21,15 +23,6 @@
 #define MIN(x, y) (((x) < (y)) ? (x) : (y))
 #define MAX(x, y) (((x) > (y)) ? (x) : (y))
 
-/* verbose */
-
-#define ERROR 0
-#define WARNING 1
-#define INFO 2
-#define DEBUG 3
-
-#define VERBOSE(level, statement...) do { if (level <= verbose) { statement; } } while(0)
-
 /* gobal variables */
 
 char *progname = NULL;
@@ -96,14 +89,22 @@ int main (int argc, char *argv[])
     while ((n = read (stdfdin, pt, BUFFER_SIZE - (pt - buffer))) != 0) {
         VERBOSE (DEBUG, PRINTOUT ("read %d bytes\n", n));
         n += (pt - buffer);
+        if ((n == 2) && (buffer[0] == '.')) {
+            return 0;
+        }
 
         /* look for end of line */
         for (i = 0, j = 0; i < n; i++) {
             if (buffer[i] == '\n') {
                 buffer[i] = 0;
                 VERBOSE (DEBUG, PRINTOUT ("line(%d): %s\n", j, buffer + j));
+                element_t *element = parser (buffer);
+                if (element == (void *)(-1)) {
+                    VERBOSE (WARNING, PRINTOUT ("error while parsing: %s\n", buffer));
+               } else {
+                    print_element (element, 0);
+                }
                 //fsync (stdfdout);
-                fflush (stdout);
                 j = i + 1;
             }
         }

diff --git a/debug.c b/debug.c
new file mode 100644 (file)
index 0000000..f2ff1ce
--- /dev/null
+++ b/debug.c
@@ -0,0 +1,5 @@
+#include "debug.h"
+
+int verbose = 2;
+
+/* vim: set ts=4 sw=4 et */

diff --git a/debug.h b/debug.h
new file mode 100644 (file)
index 0000000..b973955
--- /dev/null
+++ b/debug.h
@@ -0,0 +1,21 @@
+#ifndef __DEBUG_H__
+#define __DEBUG_H__
+
+/* constants */
+
+#define DEBUG 3
+#define INFO 2
+#define WARNING 1
+#define ERROR 0
+
+/* macros */
+
+#define VERBOSE(level, statement...) do { if (level <= verbose) { statement; } } while(0)
+
+/* gobal variables */
+
+extern int verbose;
+
+#endif /* __DEBUG_H__ */
+
+/* vim: set ts=4 sw=4 et */

diff --git a/parser.c b/parser.c
new file mode 100644 (file)
index 0000000..677f9a4
--- /dev/null
+++ b/parser.c
@@ -0,0 +1,235 @@
+#include <malloc.h>
+#include <stdlib.h>
+
+#include "debug.h"
+#include "fdprintf.h"
+
+#include "parser.h"
+
+/* compare codes */
+
+int codecmp (char *ref, char *str)
+{
+    int sig;
+
+    while (*ref != '\0') {
+        sig = *str++ - *ref++;
+        if (sig != 0) {
+            return (sig > 0) ? 1 : -1;
+        }
+    }
+
+    return 0;
+}
+
+/* allocate new element */
+
+element_t *newelement (func_t function, int nbops)
+{
+    element_t *new = (element_t *) calloc (1, sizeof (element_t));
+    if (new == NULL) {
+        VERBOSE (ERROR, fdprintf (stdfderr, "can't allocate memory\n"));
+        return NULL;
+    }
+    new->func = function;
+    new->nbops = nbops;
+
+    return new;
+}
+
+/* functions */
+
+#define NB_OPERATORS 7
+
+keyword_t operators[NB_OPERATORS] = {
+    { "+ ",  Add, 2, 1 },
+    { "+\t", Add, 2, 1 },
+    { "- ",  Sub, 2, 1 },
+    { "- ",  Sub, 2, 1 },
+    { "*",   Mul, 2, 1 },
+    { "/",   Div, 2, 1 },
+    { "^",   Pow, 2, 1 }
+};
+
+#define NB_FUNCTIONS 7
+keyword_t functions[NB_FUNCTIONS] = {
+    { "sqrt", Sqr, 1, 4 },
+    { "pow",  Pow, 2, 3 },
+    { "cos",  Cos, 1, 3 },
+    { "sin",  Sin, 1, 3 },
+    { "atan", Atn, 1, 4 },
+    { "exp",  Exp, 1, 3 },
+    { "log",  Log, 1, 3 }
+};
+
+/* parser function */
+
+element_t *parser (char *str) {
+    element_t *root = NULL;
+    int i;
+
+    /* main loop */
+    while (*str != '\0') {
+        int found = 0;
+        element_t *new = NULL;
+        VERBOSE (DEBUG, PRINTOUT ("Processing: %s\n", str));
+
+        /* skip spaces and tabs */
+
+        if ((*str == ' ') || (*str == '\t')) {
+            str++;
+            continue;
+        }
+
+        /* look for operators */
+
+        for (i = 0; i < NB_OPERATORS; i++) {
+            keyword_t *operator = operators + i;
+            if (codecmp (operator->keyword, str) == 0) {
+                if ((root) && (root->func == Val)) {
+                    VERBOSE (DEBUG, PRINTOUT ("Oper: %d\n", operator->func));
+                    new = newelement (operator->func, operator->nbops);
+                    if (new == NULL) {
+                        return (element_t *)-1;
+                    }
+                    new->ops[0] = root;
+                    root = new;
+                 } else {
+                    return (element_t *)(-1);
+                }
+                str += operator->offset;
+                found = 1;
+                break;
+            }
+        }
+        if (found) {
+            VERBOSE (DEBUG, PRINTOUT ("stop processing operator\n"));
+            continue;
+        }
+ 
+        /* look for functions */
+
+        for (i = 0; i < NB_FUNCTIONS; i++) {
+            keyword_t *function = functions + i;
+            if (codecmp (function->keyword, str) == 0) {
+                if (root == NULL) {
+                    VERBOSE (DEBUG, PRINTOUT ("Func: %d\n", function->func));
+                    new = newelement (function->func, function->nbops);
+                    if (new == NULL) {
+                        return (element_t *)-1;
+                    }
+                    root = new;
+                 } else {
+                    return (element_t *)(-1);
+                }
+                str += function->offset;
+                found = 1;
+                break;
+            }
+        }
+        if (found) {
+            VERBOSE (DEBUG, PRINTOUT ("stop processing function\n"));
+            continue;
+        }
+
+       /* last attend to detect addition and substraction */
+
+       if (((*str == '-') || (*str == '+')) &&
+           ((*(str + 1) >= '0') && (*(str + 1) <= '9')) &&
+           ((root) && (root->func == Val))) {
+            VERBOSE (DEBUG, PRINTOUT ("Oper: %d\n", Add));
+            new = newelement (Add, 2);
+            if (new == NULL) {
+                return (element_t *)-1;
+            }
+            new->ops[0] = root;
+            root = new;
+       }
+
+        /* look for number */
+
+        if (((*str >= '0') && (*str <= '9')) ||
+            (*str == '.') || (*str == '-') ||(*str == '+')) {
+            char *pt;
+            float value = strtof (str, &pt);
+            VERBOSE (DEBUG, PRINTOUT ("Value: %f\n", value));
+            if (str != pt) {
+                new = newelement (Val, 1);
+                new->value = value;
+                if (new == NULL) {
+                    return (element_t *)-1;
+                }
+                if (root == NULL) {
+                    root = new;
+                } else {
+                    for (i = 0; i < root->nbops; i++) {
+                        if (root->ops[i] == NULL) {
+                            root->ops[i] = new;
+                            found = 1;
+                            break;
+                        }
+                    }
+                    if (!found) {
+                        return (element_t *)-1;
+                    }
+                }
+                str = pt;
+                found = 1;
+            }
+        }
+
+        /* error */
+
+        if (!found) {
+            return (element_t *)-1;
+        }
+
+    }
+
+    return root;
+}
+
+/* print element tree */
+
+void print_element (element_t *root, int level)
+{
+    char *func = NULL;
+    int i;
+
+    if (root == NULL)
+        return;
+    
+    for (i = 0; i < level; i++) {
+        PRINTOUT (" ");
+    }
+
+    switch (root->func) {
+    case Val: func = "Value"; break;
+    case Add: func = "Addition"; break;
+    case Sub: func = "Subtraction"; break;
+    case Mul: func = "Multiplication"; break;
+    case Div: func = "Division"; break;
+    case Pow: func = "Power"; break;
+    case Sqr: func = "Square Root"; break;
+    case Cos: func = "Cosine"; break;
+    case Sin: func = "Sine"; break;
+    case Atn: func = "Arc Tangent"; break;
+    case Log: func = "Logarithm"; break;
+    case Exp: func = "Exponantial"; break;
+    }
+
+    PRINTOUT ("Function: %s\n", func);
+
+    if (root->func == Val) {
+        for (i = 0; i < level; i++) {
+            PRINTOUT (" ");
+        }
+        PRINTOUT ("value: %f\n", root->value);
+    } else {
+        for (i = 0; i < root->nbops; i++) {
+            print_element (root->ops[i], level + 1);
+        }
+    }
+}
+
+/* vim: set ts=4 sw=4 et: */

diff --git a/parser.h b/parser.h
new file mode 100644 (file)
index 0000000..4650007
--- /dev/null
+++ b/parser.h
@@ -0,0 +1,42 @@
+#ifndef __PARSER_H__
+#define __PARSER_H__
+
+/* function type */
+
+typedef enum {
+    Val = 0,
+    Add, Sub,
+    Mul, Div, Pow,
+    Sqr,
+    Cos, Sin, Atn,
+    Log, Exp
+} func_t;
+
+/* keyword type */
+
+typedef struct _keyword_t {
+    char *keyword;
+    func_t func;
+    int nbops;
+    int offset;
+} keyword_t;
+
+/* calculus element type */
+
+#define MAX_OPERANDS 2
+typedef struct _element_t {
+    func_t func;
+    int nbops;
+    struct _element_t *ops[MAX_OPERANDS];
+    float value;
+} element_t;
+
+/* parser function */
+
+element_t *parser (char *str);
+
+void print_element (element_t *root, int level);
+
+#endif /* __PARSER_H__ */
+
+/* vim: set ts=4 sw=4 et: */